1. Field of the Invention
The present invention pertains to the art of cooking appliances and, more particularly, to a convection oven incorporating a pressure sensor in a recirculating air flow path for use in controlling at least one heating element of the cooking appliance.
2. Discussion of the Prior Art
It is known in the art of cooking appliances to utilize multiple heating elements within a single oven cavity for use in connection with baking, broiling and/or cleaning modes of operation. It has also been proposed in the art to incorporate a fan within the cooking appliance to enhance the flow of heated air through the oven cavity in order to provide for a more uniform temperature distribution and reduce required cooking times within the oven.
Regardless of these known prior art arrangements, there exists a need for further enhancements in the control of the heated air flow for a convection oven. More specifically, since the heating element(s) is actually being cooled by the convection air flow, it is possible to operate the heating element(s) at a higher temperature, which can further reduce cooking times. However, if a higher operating temperature is established and the air flow was decreased, the result could be damage to the heating element(s). When electric heating elements are employed, a high resistance short to the chassis of the cooking appliance can also be created.
Based on the above, there exists a need in the art of cooking appliances for a convection oven arrangement with enhanced control features which enables one or more electric heating elements to operate at relatively high temperatures when a flow of air is directed across the heating element(s), while automatically reducing an operating temperature of the heating element(s) when the flow is disrupted.
In accordance with the invention, a convection cooking appliance is provided with at least one electric heating unit disposed outside an oven cavity of the cooking appliance. More particularly, the heating unit is disposed in a duct section of an air channel assembly which extends about and is in fluid communication with the oven cavity. A flow of air is directed through the channel assembly by a blower. In the most preferred form of the invention, a pressure sensor is employed to sense air pressure within the air channel assembly. The pressure sensor is linked to a controller for the heating unit in order to reduce or interrupt a current supply to the heating unit when the air pressure drops below a threshold value.
In the most preferred embodiment of the invention, the heating unit is centered in the air flow stream and arranged continuous from side-to-side. The heating unit preferably defines a single coil extending in various rows, with each of the coil rows being arranged substantially perpendicular to the flow of air. With this configuration, the heating unit tends to interrupt any developing patterns of air flow other than a linear flow in a desired direction. Furthermore, the pressure sensor is preferably positioned so as to sense the pressure in the air channel assembly directly adjacent the heating unit.